Particulate ladings, such as polycarbonate or thermoplastic materials, synthetic resins, for example, are normally loaded within boxes, bags, containers or the like at a site where the polycarbonate plastic material is manufactured, and then transported by wheeled vehicle to a site where the plastic material is unloaded from the container into a storage facility for subsequent use in the manufacture of various plastic end products. It is highly desirable that such plastic materials or ladings, such as polyethylene pellets, not be contaminated by foreign matter or the like as even small amounts of foreign matter or contamination affect the quality of the subsequent manufactured products. Heretofore, plastic liners or bags such as vinyl or polyethylene liners have been used within containers to protect the lading from contamination. The plastic liners are normally sealed at the initial loading site and the lading is maintained in sealed relation within the plastic liner until unloaded at the unloading site, thereby insuring that the plastic lading will not be contaminated. Normally, the plastic lading is unloaded at the unloading site from the container by a suction or vacuum line extending within the container and then is conveyed pneumatically to a storage facility, such as bins, silos, or the like, until needed for the production of plastic end products. Pressurized air is sometimes used to push or aid in pushing the particulate material from a container into a pneumatic discharge line for pneumatically conveying the particulate material into the storage facility.
Heretofore, such as shown in U.S. Pat. No. 4,875,811 dated Oct. 24, 1989 and U.S. Pat. No. 5,096,336 dated Mar. 13, 1992 a container has been used in intermodal transportation by mounting on railway flat cars, container ships, or highway trailers, for example, for the transport of particulate material with the particulate material being sealed in a flexible bag within the container and then unloaded at an unloading site by tilting of an end of the container. The transportation system illustrated in U.S. Pat. No. 4,875,811 transports particulate material in a sealed condition from one location or site where the particulate lading is loaded into a container having a liner or bag therein, to another location or site where the sealed liner or bag within the container is broken for unloading of the particulate lading from the container into a storage area. Such a system is utilized also for the transport of other various particulate materials, such as, for example, granular or powdered materials used in foodstuffs.
The container after being loaded and sealed at the first site is transferred to a tiltable container support frame on a highway vehicle for transport to the second site where the sealed container is broken and then tilted by a tiltable support frame to an angle above the angle of repose of the lading within the container for discharge of the lading by gravity from the container into a pneumatic discharge line for pneumatic conveying to a suitable storage facility, such as a storage bin or silo.
One end of the container has a pair of rear doors which are normally latched in closed position during transit. The bag fitting between a pair of end bulkheads is filled with lading from a flexible hose extending within an upper tubular inlet extension or neck of the bag. Upon filling of the bag with lading the bag is urged against the end bulkheads and the extending tubular extension is sealed by suitable banding or ties. Thus the lading is sealed within the bag for transport to an unloading site.
The loaded container as illustrated in U.S. Pat. No. 4,875,811 is then transferred to a tiltable container support frame pivotally mounted on a highway trailer body and is releasably secured thereon for transport by a highway vehicle to an unloading site. At the unloading site, at least one of the end doors of the container is opened and a discharge outlet for the pneumatic conveying apparatus is removably connected adjacent the rear end of the container for unloading of the container. The inner end of a lower tubular extension or spout of the bag is sealed at its juncture with the bag by a sealing membrane defined by the portion of the bag covering the inner end of the lower spout. This sealing membrane must be cut or removed in order for the lading to be unloaded from the plastic bag. Thus, the lading is tightly sealed upon loading within the plastic bag, and the plastic bag remains in a sealed condition until it is opened by slitting the membrane for gravity discharge directly into a pneumatic conveyor through the discharge outlet at the unloading site. The container or the plastic bag is not pressurized in any manner during unloading and the plastic bag collapses as the lading is removed or discharged. Thus, loss of lading after being loaded within the plastic bag in the container until the lading is discharged into the pneumatic unloading system at the unloading site is minimized.
The pneumatic conveying apparatus and the connecting lading conduits between the rear end of the container and the pneumatic conveying apparatus are positioned between the rear end of the container and the rear tandem wheels in order to permit an effective and satisfactory gravity unloading of particulate lading from the rear end of the tilted container to a rotary valve which feeds the particulate lading into an air stream in a lower pneumatic hopper for pneumatic conveyance to a storage site such as a silo, for example. A flexible lading conduit connects a throttling control valve on the discharge outlet adjacent the rear end of the tilted container and the rotary valve for the pneumatic hopper below the container for unloading the lading at a relatively fast flow rate from the container.